


Thinking Inside The Box

by ourheart



Series: Chara & Frisk Week Prompts [1]
Category: Doctor Who, Undertale (Video Game)
Genre: Bodysharing, Crossover, Female Doctor (Doctor Who), Gen, Nonbinary Chara and Frisk, Regeneration
Language: English
Status: Completed
Published: 2016-09-12
Updated: 2016-09-12
Packaged: 2018-08-14 14:13:15
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,029
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/8017138
Author URL: https://archiveofourown.org/users/ourheart/pseuds/ourheart
Summary: <blockquote class="userstuff">
              <p>“I want to hear your story,” she says, locking her eyes on yours, and you can see an ancient coldness beneath the twinkle, now. Her gaze is piercing, but not unkind. (You’re reminded of Sans in the golden hallway and try your best not to squirm.) “You’ve been busy. Going backwards over the same moments, again and again, slowly wearing out the fabric of your spacetime. A desperate child with a wish can be a powerful thing. Even dangerous, perhaps.”</p><p>Chara makes a very uncomfortable noise in your head.</p>
            </blockquote>





	Thinking Inside The Box

**Author's Note:**

> Written by Dearheart! ~~The crossover that nobody asked for but I did anyway because I'm still whovian trash, hehe.~~ This was _supposed_ to be a short drabble for the "Crossover" prompt of [Chara & Frisk Week](http://chara-and-friskweek.tumblr.com/) on tumblr, but the pages just kept coming, whoops. 
> 
> **Heads-up:** the Doctor is a woman in this. Mainly because I couldn't decide on which Doctor to write, so I made up my own regeneration instead.
> 
>  **Another heads-up:** there is a brief moment in this where a finger gets cut off and then grows back. If that makes you squeamish, tread carefully!
> 
> Hope you enjoy this! :)

In all the times you’ve reset - all the times you’ve gone back, swearing to yourself that _this_ will be it, _this_ will be the timeline when Fate agrees to let you give Chara and Asriel back to their family (loved and alive with the new second chance they deserve, please, _please_ ) - in every strand of reality you’ve searched, you’ve never found anything like this before.

The windows glow as if there’s magic inside. When you reach out, the painted wood is warm against the palm of your hand; and the strange box hums questioningly at your touch. It feels like a living thing.

 ***This is new… Will you look inside?** Chara’s voice in your head is cautious, but you can feel that they’re just as curious as you are.

Before you have a chance to make up your mind, the door swings open. Golden light spills out over the snow and across your shoes...and a woman with bright eyes and messy hair pops her head out, squinting right at you.

Not sure what else to do, you squint back.

“A _child...?_ ” she murmurs, a touch of disbelief in her tone. “ _You’re_ the anomaly?” She tilts her head, almost birdlike, and then a grin spreads across her face and she practically crows with delight. “The anomaly is a ten-year-old! Oho, this is _Christmas!_ ”

Chara is torn between incredulousness and panic. ***Who is she? What does she want with us? Frisk, don’t talk to her!**

The woman cocks her head at you again. “Wait... _is_ it actually Christmas?”

You just shrug in reply. You’ve reset so many times by now that you’ve forgotten what month or day it actually is.

She sniffs the air and experimentally pokes one foot out into the snow, then frowns over your shoulder in the direction of the Gyftrot tree. “It looks like Christmas, but it just doesn’t smell right…eh, we can worry about that later. For now, though...”

You back up a couple of steps as she hops out of the box and crouches down to your level. A strand of hair flops in her face and she wrinkles her nose, huffing through her lips to blow it out of the way.

 ***She’s so** **_weird._ **

You inwardly snort. _There are monsters here who are literally part bathtub, and you think_ she’s _weird?_

“I want to hear _your_ story,” she says, locking her eyes on yours, and you can see an ancient coldness beneath the twinkle, now. Her gaze is piercing, but not unkind. (You’re reminded of Sans in the golden hallway and try your best not to squirm.) “You’ve been busy. Going backwards over the same moments, again and again, slowly wearing out the fabric of your spacetime. A desperate child with a wish can be a powerful thing. Even dangerous, perhaps.”

Chara makes a very uncomfortable noise in your head.

Your eyes flicker down to your shoes, then back up to her, fingers fidgeting with the hem of your sweater before you sign. “ _Are you friends with Sans?_ ”

“Mm, maybe I could be. Is Sans a friendly person?”

“ _Who are you?_ ”

“I’m the Doctor!” she announces, proud and matter-of-fact. “And thank you for asking! That’s the first time I’ve gotten to tell anyone with this voice.”

“ _I don’t understand._ ”

“I’ve never been a girl before, you see.” The Doctor leans forward a little, like she’s imparting the secrets of the universe. “I only regenerated yesterday. Still getting used to everything. New voice, new hair, new face, and I _still_ haven’t decided on which overcoat I like...oh!” Her eyes light up with a new idea. “You should help me pick!”

You blink, totally lost. (By now, Chara’s voice has become a drone of: ***No, no, no, heck no,** ** _no…_ ** )

The Doctor nods firmly before you can answer and she springs to her feet again, placing her hands on her hips. “Alright, it’s decided. The ten-year-old time anomaly will be my fashion consultant for the day. Come along, err...what’s your name?”

“ _F-R-I-S-K._ ”

“Lovely! Come on in, Frisk! My TARDIS will behave herself, I promise.” She spins in place with excitement and prances back inside the blue box, leaving you alone for a moment with your literal soul-mate and an open door to consider.

Chara sighs in relief. ***Finally. Let’s get out of here.**

_I don’t know._

***Well** **_I_ ** **do. I don’t like this. Or her. She’s a human, she’s weird, and we can’t trust her. Period.**

_Chara, you said it yourself. This is new. I don’t know how she got here or why, but...don’t you think it’s a hint we should stay on this track? That this could be a chance to find what we’re looking for?_

***...**

_We have to try. For Asriel._

***…Yeah. Okay. Just be careful. SAVE points or not, I don’t want anything happening to you, too.**

_Aww, you Chara-bout me._

***I take that back. I hope she strangles you.**

You stifle a victorious snicker at Chara’s disgust. And then, gathering your determination, you straighten your shoulders and step through the narrow doorway with your hands hovering, fingertips waiting to brush against the back...

But the back of the box never comes.

You blink in the unfamiliar light, breath catching in your throat from the shock. You can’t keep your mouth from falling open when you look around at the wide, shining walls, winking and beeping with mysterious buttons, and the columns and tall ceiling arching over you like an alien cathedral.

 ***Holy shit,** Chara breathes.

The Doctor is reclining back against a circular console in the middle of the room, an expectant smirk on her lips as she watches you. “Go ahead and say it. I _love_ when people say it.”

You know she’s waiting for you to comment on the inside being bigger than the outside, but instead, you find enough presence of mind to smirk back and point around you, signing: “ _It._ ”

Her eyebrows raise in surprise at your cheek, and then she tosses her head back and laughs. “Oh, you’re a clever one, aren’t you! Okay then, enough with the theatrics...”

You watch her dart around the room for the next few minutes, pulling out various overflowing racks of clothing and chattering away about her beloved TARDIS. “Time And Relative Dimension In Space,” she declares, rapping her knuckles affectionately against the console as she throws an old tie over her shoulder. “This ol’ girl can take you anywhere, anywhen!”

You quietly tuck away everything she tells you, nodding an occasional “yes” or “no” at her as she tries on various coats and asks for your opinion. In distracted bits and pieces, she explains that it’s like a spaceship and a time machine, only far more special because it’s alive! She tells you she likes to travel, and sometimes her TARDIS won’t pay attention to the destination she’s aiming for, and it’s _such_ a nuisance. She’s developed a fondness for reggae, she once saved the world with a banana, and oh yes, she’s actually an alien from the planet Gallifrey--

“Yeah, right,” Chara says with your voice, slipping into control before either of you know it. They realize what they’ve done and shut your mouth again, mentally kicking themself and apologizing. (You reassure them that you don’t mind, that it’s only fair they get to talk to her too, and they relax a bit.)

“It’s true, though!” the Doctor protests, shrugging on a burgundy overcoat with shiny black buttons and twisting in front of a nearby mirror. “I really _did_ save the planet with a banana. It’s actually a very interesting story--”

“Stop it,” Chara snaps again, impatient. “You’re obviously human, and I’m not stupid. You think just because you have a weird machine I’ll buy all your bullshit? Why the hell would you look like a human if you’re actually an alien? Oh, I don’t know, maybe because you’re a creepy _liar_ who thinks you can make a kid believe _anything_ if you dazzle them enough.”

(Chara’s fighting words make you nervous. You aren’t sure you want to risk making her angry, but...they do have a point. You keep silent, and observe.)

The Doctor pauses, studying her reflection, and then turns on her heel to stroll back to you, her expression unreadable. There is stern purpose in the way she carries herself now; and you’re both suddenly struck by how tall this woman is, how old her eyes look.

“You want me to prove I’m not human, little anomaly?”

Chara falters, swallows, and sets their jaw with a glare. “Yes.”

“Mmm. I get the sense you aren’t fond of other humans in general. Am I right?”

“...Yes.”

Something like sympathy flickers in her eyes, and then she shrugs. “Fair enough.”

She sweeps back the flaps of her coat to pat down her pants, searching. When her hand dips into her right pocket, she pulls out something that looks like a closed pocketknife.

Chara starts and skuttles back in alarm. “If you even _try_ to--”

“I’m not pointing it at you, am I?” The Doctor’s voice is calm and firm, like a nurse about to administer a shot. “I’m not going to hurt you. Just watch me.”

Her thumb presses a button on the side, and instead of a blade, a small, red beam of buzzing energy appears. Chara is still poised to run or fight if needed, but they watch. Your presence clings tightly to theirs and you watch, too.

“This will be gross,” she warns, before holding out one finger and bringing the laser-knife down on it, cutting it clean off.

You and Chara both gasp and flinch - you in shock, Chara in morbid fascination. The wound is cauterized, so there’s no blood, but it still looks gruesome. You can’t bring yourself to look at what’s on the floor now.

The Doctor seems completely unperturbed. She puts the laser-knife away, wraps the newly-cut pointer finger in a handkerchief and puts _that_ in her pocket, too (you both shudder); and then holds up the hand with the wound, displaying it to you. “Okay, grossest part over. Time for the creepy part. If I was human, would I be able to do this?”

You both stare as wisps of soft light curl around her hand. New skin slowly stretches over the wound and begins to bubble upwards, a stub growing where the missing finger used to be. In under a minute, a new finger has joined the others, perfectly formed.

Your jaw is hanging open again.

“You’re lucky my latest regeneration happened so recently,” she remarks, turning her hand back and forth to inspect the new appendage. “I might not’ve had the leftover energy to pull that off, otherwise.”

Chara’s presence slinks back, giving full control to you again.

“So. Is that proof enough?”

You close your mouth and sign, “ _Yes. We...I believe you._ ”

“Good!” she chirps, wiggling the new finger at you.

Your nose wrinkles in response and she chuckles, crouching down like before to sit on her heels, elbows resting on her knees. Her gaze feels scrutinizing again, but you refuse to look away this time.

“Now, Frisk. I’m curious. Where did the other person just go?”

You feel a cold jolt in your gut, but you try to keep your expression blank. Your fingers stay steady. “ _I don’t know what you mean._ ”

“Oh, come now,” she drawls, shooting you a dry, knowing smile. “I’m a timelady who’s traveled the universe, I’ve been around so long I can’t remember my age anymore, and I know multiple consciousnesses in one body when I see them. Plus, you _did_ just accidentally sign ‘we’.”

You suppress a wince at the mistake.

“Normally I’d break into singing ‘The Crystal Gems’ - catchy song, that! - but right now I’m much more interested in learning about you.” The Doctor steeples her fingers in thought and rests her chin against them. “There’s obviously at least two of you in that head, somehow. Not sure about your friend, but I know _you’re_ quite human. If my readings are right...it seems the energy of this place combined with your own sheer willpower is letting you manipulate time, to a certain degree. No TARDIS needed there, eh?”

You shrug, still keeping your face blank.

 ***I wish she’d shut up and leave us alone,** Chara mutters.

“And yet...even when you have the ability to go forward...you keep riding the current back downstream. You loop around and around, over and over, when you could easily stop it. If you wanted.”

You chew on your bottom lip, and still say nothing.

She lets out a breath, eyes softening. “A desperate child with a wish,” she murmurs. “You wouldn’t be the first. Tell me...what is your wish, Frisk? What is it that you and your friend are still looking for?”

***...**

The question hangs in the air for a moment.

You whisper: “A happy ending.”

“For who?”

“ _For...everyone._ ” You go back to signing. Your throat is tight and your fingers tremble with the force of the movements. “ _No one left behind. Not one person. Because it’s not fair. It’s not._ ”

You don’t notice you’re crying until she reaches out with her right hand - the same one that so easily cut herself - and brushes the tears away as gently as a mother would. You feel Chara’s warmth wrap around your soul in an unseen hug, their own guilt and sorrow spilling into yours.

Her smile is bittersweet. “A story where, just once, everybody lives. Those stories are rare. But...not impossible, in my experience. Not always.”

“ _I don’t want to think about impossible._ ”

“Neither do I, little anomaly.”

You scrub your sleeve over your eyes and look at her again, mouth set in a firm line as stubborn resolve hardens in you. “ _Help us. Please. I know you can._ ”

“I don’t call myself The Doctor for nothing,” she says, standing up and straightening her coat. “I like to make things better, where I can. I’m...not always the best at it. But, nonetheless, it is what I strive for. I’m always a sucker for happy endings.”

Chara perks up, tentative. ***Wait…is she really agreeing to…**

“ _You’ll really do it?_ ” Hope leaps in your chest, bright and aching.

She holds up her hands. “I can’t make any promises. There are some points in time that are fixed and unchanging. Some lives that are destined to slip through your fingers, no matter how tight you grasp. But…” Her lips quirk tenderly. “I can never say ‘no’ to a child who’s been crying. Especially when that sadness is big enough to break reality itself.”

You’re overcome with so much relief and gratitude that you can’t help yourself - you rush forward and throw your arms around her, burying your face in her middle. After an awkward second, she returns the embrace, patting your back.

 ***Jeez, Frisk. Do you have to hug** **_every_ ** **weirdo you meet?**

_Yep!_

“There, there,” the Doctor soothes. “We will search for this happy ending together, alright? No more tears or groundhog days. We have a new adventure to get to!”

You pull away and nod, beaming up at her. “ _Thank you. Thank you so much._ ”

“Don’t thank me yet, kids. Oh! I almost forgot!” She steps away from you with a grin and twirls in her overcoat, arms outstretched, striking a pose when she stops. “How do I look?”

The rich burgundy color and the black accents are striking on her. You give her a wink as you sign, “ _Is it hot in here, or is it just you?_ ”

You can almost _physically_ feel Chara drop their face into their hands. ***Oh my god, why.**

“Ohoho, getting _frisky_ now, are we?” She chortles and wags a finger at you. “You certainly know how to sweet-talk a lady, but I’m afraid I’m about a billion Earth-years too old for you.”

You giggle and let your hands flop in an oh-well gesture. “ _It looks great on you. You should keep that one._ ”

She skips back to the mirror, admiring the view, turning this way and that until she nods in satisfaction.

“It _does_ suit me, I think. Good call! Now then...” Frowning at the clothes strewn about on the floor, she kicks them out of her path before shoving the clothing rack behind her and sending it rolling away on noisy little wheels. She claps and rubs her hands together as she strides back to the console, all business...but there’s a lightness in her steps, and you can see the playful spark in her eyes again.

The TARDIS blips and purrs as she pushes buttons and twists knobs, fingers flying over the controls like she’s playing a one-woman symphony. (Maybe she is, for all you know.) You walk over to watch, taking a moment to glance up at the immense ceiling again, and breathe deeply.

 ***This is really happening,** Chara says, floaty and faraway. ***Asriel...we actually have a chance to save him now, don’t we…?**

_Or a chance of a chance, at least._

You feel it too. The dizziness of _finally_ seeing solid hope in front of you, and still being unsure that you can touch it.

 ***Frisk. You didn’t have to try so hard for him, or for me, but I…um. Thanks. For all of this.** Though the words are stiff, Chara’s sincerity is warm and earnest inside you. **Even if this doesn’t work out...you don’t know how much it means to me. That you’d go this far for us, that you…** ** _care_ ** **so much. I still don’t understand it sometimes, but…I just… Yeah. Thank you.**

You smile softly and focus on wrapping your presence around theirs, holding them close inside your soul. _You’re my best friends, and I’m stubborn. It’s as simple as that._

***Heh.**

The Doctor turns and winks at you. “Let’s get started on saving the day, shall we?”

Lifting your chin, you nod.

The box is bigger on the inside, and the Doctor can make it go anywhere in all of spacetime. That’s two miracles you’ve found today. Maybe, if you’re lucky, you can find one more.

( ***Knowing this...it fills you with determination.** )


End file.
